It is the purpose of this research project to utilize the recent findings on the photoaffinity labeling of the human placental glucose transporter, given in the Appendix A manuscript, to further characterize the glucose transporter. The information obtained should advance the understanding of the sodium-independent glucose transport system, which is important in many tissues. More specifically, since most of fetal oxidative metabolism is based on glucose, these findings should provide information pertinent to placental transport and fetal nutrition. Also, the information obtained should be relevant to studies of pathological states. Diabetes mellitus in human pregnancy is associated with increased mortality and morbidity in the infant. Since insulin regulates sodium-independent glucose transport in some tissues, a greater understanding of the mechanism of glucose transport and its regulation may shed light on the pathophysiology of diabetes. Furthemore, alterations in malignant cel metabolism may in part be a consequence of increased glucose transport in at least some tumors and it has been suggested that the placenta is a good model for the study of normal and abnormal cell function. Many of its metabolic activities vary little from those of a tumor. Consequently, the studies proposed in this application may provide important baseline information relevenat to oncologic as well as other research.